CONVERTER CIRCUIT HAVING OVERVOLTAGE PROTECTION

摘要

For a drive system of an electric car comprising a DC battery, a permanently excited synchronous machine in field-weakening operation as an electric motor, and a converter connected therebetween, a diode is inserted in the connection between the positive battery terminal and the converter in order to block positive voltages from the converter. Overloading and destruction of the battery in the event of a malfunction of the converter are thereby prevented. An IGBT provided in parallel with the diode is switched on to bypass the diode if a regular recovery from the motor into the battery should occur. In the event of a malfunction, the IGBT is switched off.